In many industries it is required to set up an array of equipment at a temporary work site, and then disassemble the installation, move it to another work site, and re-assemble it. For example asphalt and concrete plants are often set up in locations where large quantities of material are required for road or building construction. Similarly well drilling rigs, such as those drilling for oil and gas, are set up at a drilling location, then taken down and moved to a different drilling location.
These portable plants and rigs typically include various tanks, bins, silos, and the like for water, asphalt, sand, cement, and other materials such as might be required at any particular work site. These are transported to the work site, commonly in a lowered horizontal transport orientation, and then raised to a vertical working orientation at the work site. For example bins containing dry material especially are often elongated vertically when in a working position to maximize the quantity of material stored above a hoppered bottom such that the dry material will flow out by gravity.
This vertical orientation also reduces the ground area, or footprint, occupied by the installation. For example in well drilling installations it is necessary to have a number of different materials located in proximity to the well being drilled, and the vertical orientation of tanks and bins facilitates such proximity. In other installations it may also be desirable to minimize the area occupied.
Bins and tanks are typically carried by flat bed trucks or trailers to the work site. The trailer is maneuvered into position, and then the container is raised from the horizontal transport position to a vertical working position resting on the ground, and the trailer is moved away from the site. A loader machine or crane can be used, or in some cases the trailer may include a tilt up deck or hoist to raise the object to the vertical, or near vertical position. Tipping and dumping vehicles are well known for a wide variety of purposes where the load carried is tilted upward from a substantially horizontal transport position.
At a work site such as an asphalt or concrete plant, oil or gas well, or the like it is generally required to orient the bin or tank so that the contents can be removed as required. Where the contents are liquid generally an outlet port with a valve is provided so that conduits can be connected to deliver the liquid where required. A pump may also be required to move the liquid to the desired location of use. Orienting the outlet port on the tank close to the use location can shorten or simplify the conduit configuration, but generally orientation of the outlet is not critical, since liquid material can readily be delivered through a conduit network. Where the location of the outlet port is more critical, extra ports can be provided to enable an operator to draw liquid out of the tank at multiple locations.
Where the contents are granular, such as sand, cement, or the like, orientation of the outlet port is more critical. Containers holding granular material typically have a hoppered bottom to direct the last granular material out through the outlet port when the container is getting empty. Thus it is not generally possible to conveniently provide multiple outlet ports on a granular material container, and the outlet port is thus in a fixed location. Granular material also cannot flow or be easily pumped through a conduit, and so it is commonly required to provide a conveyor to move the granular material from the outlet port to the use location. Such conveyors are typically fixed in length and do not have the flexibility of conduits such as hoses used for liquid material. Thus orientation of a container for granular material when it is raised to the working position is more problematic. In order to properly orient the container the trailer carrying the container must be maneuvered to get the desired orientation, often in a limited area obstructed by other tanks, bins, and equipment.
U.S. Pat. No. 3,547,291 to Batterton et al. for example discloses an erection means for a transport trailer. A bin is carried on a flatbed trailer in a horizontal orientation. The bin is pivotally attached to the rear end of the trailer, and actuators bear against the bin and trailer to pivot the bin up to the vertical position. The apparatus is configured such that when the bin is vertical the floor of the bin is on the ground. The bin is then disconnected from the trailer and actuators and the trailer is driven away.
United States Published Patent Application Number 2010/196130 of Herman et al. discloses a transportable container and a trailer pivotally attached to one side of the container. In a working position the trailer is pivoted up to a vertical orientation along the side of the container, such that other equipment can be located closely adjacent. When it is time to relocate the container, an actuator pivots the trailer downward about the pivot axis to a transport position where the trailer rests on the ground and extends horizontally away from the container such that a hitch can be connected to a tow vehicle. When the hitch is connected to a tow vehicle, the actuator can then be operated to pivot the main body downward about the pivot axis to a lowered transport position where the main body rests on the trailer for transport in a horizontal position.
A problem with such relatively narrow and tall elongated containers is that when empty they are somewhat unstable, especially where the ground is not level, as often occurs at temporary work sites. When filled, the weight of the contents keeps the container in place but when empty, winds or accidental contact with other equipment being moved at the work site can cause the container to tip over. The stability of such containers is commonly calculated as an empty wind load rating based on the wind velocity necessary to tip the container over.